Aluminum alloy plate based on dynamic diffusion field regulation

Abstract

A kind of 6451 aluminum alloy plate based on dynamic diffusion field regulation belongs to the field of aluminum alloy digital manufacturing technology.The raw material is melted and refined into ingot according to set composition, then the ingot is cut and milled after being put into heat treatment furnace for homogenization treatment, the ingot after homogenization treatment is cooled to hot rolling temperature for a period of time and then hot rolling starts.After hot rolling, the obtained hot rolled plate is cold rolled and intermediate annealed, then cold rolled to the thickness of final product plate, the obtained cold rolled plate is treated by solid solution, water quenching and then pre-aging treatment, the finished plate is obtained, the finished plate is treated by baking finish, and the final plate is obtained.The present application strictly controls the preparation process, ensures the plate under the premise of low initial yield strength, realizes high baking hardening performance, and is better suitable for automobile structural parts with high forming requirement, high strength requirement and high impact performance.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of digital manufacturing of aluminum alloys, in particular to a 6451 aluminum alloy plate based on dynamic diffusion field regulation. BACKGROUND

[0002] The 6451 aluminum alloy belongs to the 6-series Al-Mg-Si alloy with medium-high strength, and has excellent properties such as good formability, high baking strength and good energy absorption effect, and is widely used in automobile body structure parts such as longitudinal beams, threshold beams, bottom plate beams, floors, roof covers and door inner plates. The solute element Mg and Si contents of the 6451 alloy are higher than those of conventional 6016 and 6014 alloys, so that a higher baking strength is obtained to improve the crash performance, while the problem of too high yield strength reducing the formability exists.

[0003] The 6-series aluminum alloy is subjected to solid solution heat treatment to regulate the solid solution degree of solute atoms and then regulate the precipitation strengthening phase in the matrix, so that a higher strength is obtained, and the initial yield strength of the alloy is also increased, thereby reducing the stamping formability of the alloy.

[0004] In order to meet the best load transmission path of the automobile body structure parts, the 6-series aluminum automobile plate should have a suitable yield strength to ensure excellent stamping formability, and the crash performance of the automobile body structure parts should be considered. The 6-series alloy should also have a higher baking strength. The energy absorption performance during the crash deformation process of the automobile structure parts is the focus of the industry, and the bending angle is used as a means to measure the crash energy absorption. The aluminum alloy plate for automobile structure parts needs a higher bending angle.

[0005] In recent years, some domestic universities and research institutions have carried out a lot of work on the mechanical properties and crash performance of 6-series aluminum alloy plates. At present, most researchers mainly focus on the optimization and simulation calculation method of the automobile body structure, and the research on improving the crash performance of the material is relatively less. The patent CN118186277A uses modified basalt fibers to improve the toughness of the aluminum alloy. The modified basalt fibers are in the form of circular tubes and have higher energy absorption capacity. When the aluminum alloy is impacted, the modified basalt fibers can disperse the impact force and disperse the force to the shell structure reinforcing particles, thereby enhancing the fracture toughness of the aluminum alloy. However, the composite material has the disadvantages of high cost and poor process stability, and cannot be widely applied in the automobile field. The aluminum alloy prepared in the patent CN113981281A can reach a peak value in a relatively short time, and the yield strength R p0.2 of the high-strength rapid aging aluminum alloy is greater than or equal to 265 MPa, and the tensile strength R m≥307MPa, elongation A-(50) ≥5.5%, a higher strength is obtained, but the yield strength is too high, the alloy forming property cannot be guaranteed, and the complex forming requirement of automobile parts cannot be met. The patent CN119389309A optimizes the aluminum alloy vehicle body structure, simplifies the structure, improves the space utilization, improves the bending and torsion of the vehicle body and the crash performance, improves the side crash and side column crash safety performance, and improves the torsional stiffness and side crash performance of the vehicle body, but does not involve the improvement of the material crash performance. The patent CN115831289A establishes a material model through the stress-strain curve of the material under various temperature and humidity conditions, is configured to meet the basic performance requirements under the preset temperature and humidity range, obtains the forming target structure, and performs crash simulation, simplifies the test process, and reduces the test difficulty and cost, but does not provide the research on improving the crash performance of the material under different temperature and humidity environments. The patent CN112195376A innovates the double-stage pre-aging process, controls the cluster of the strengthening phase beta" phase formed by the baking treatment, and improves the baking hardening performance of the plate, but the holding time of the solid solution process is long, the production efficiency is low, and the current demand for high efficiency production cannot be met. In addition, the current double-stage homogenization process cannot be industrialized. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application studies the influence of solid solution conditions on yield strength, baking strength and bending performance, and provides a 6451 aluminum alloy plate based on dynamic diffusion field regulation. The 6451 aluminum alloy prepared by the method provided by the present application not only has appropriate initial yield strength, high baking hardening performance, but also has high crash performance.

[0007] The present application is realized by the following technical solutions:

[0008] A 6451 aluminum alloy plate based on dynamic diffusion field regulation, the plate comprises the following components in mass percentage: Si: 0.7wt.%-1.3wt.%, Fe: ≤0.5wt.%, Cu: ≤0.15wt.%, Mn: ≤0.20wt.%, Mg: 0.5wt.%-1.5wt.%, Cr: ≤0.10wt.%, Zn: ≤0.15wt.%, Ti: ≤0.10wt.%, and the balance is Al and impurities with a content less than 0.05wt.%.

[0009] The initial yield strength of the plate is 104MPa-115MPa, the solid solution amount is 4.18μm-8.64μm, and the elongation is ≥25%; the yield strength after baking is greater than 235MPa, and the bending angle after baking is ≥80°.

[0010] The initial yield strength of the aluminum alloy plate and the solid solution amount comply with the functional relationship formula:

[0011] ;

[0012] wherein R p0.2 is the initial yield strength, S is the solid solution content.

[0013] The preparation method of the 6451 aluminum alloy plate based on dynamic diffusion field regulation comprises the following steps:

[0014] Step 1. After mixing the components of the plate according to the proportions, melting and refining, the semi-continuous casting equipment is used to cast ingots;

[0015] Step 2. Homogenize the ingot: control the heating temperature to be 540-580℃, and the holding time to be 6-10h;

[0016] Step 3. The homogenized ingot is sequentially subjected to hot rolling, primary cold rolling, intermediate annealing, and secondary cold rolling. The hot rolling process is as follows: the opening rolling temperature is 525-540℃, the hot rolling is performed to a plate thickness of 5-8mm, and the final rolling temperature is 260-280℃; the primary cold rolling is performed to a plate thickness of 3-4mm; the intermediate annealing temperature is 470-500℃, and the holding time is 20-40s; the secondary cold rolling is performed to a plate thickness of 0.8-1.5mm; and the cold rolling reduction rate is ensured to be 50-80%;

[0017] Step 4. The plate obtained by secondary cold rolling is subjected to solid solution treatment: the holding temperature is 560℃, and the holding time is 7-30s;

[0018] Step 5. The solid-solution-treated plate is quenched and cooled at a set cooling rate by combining spray with strong air cooling;

[0019] Step 6. The plate quenched and cooled is subjected to straightening treatment;

[0020] Step 7. The straightened plate is transferred to a temperature of 60-100℃ for 4-10h of pre-aging treatment to obtain a finished plate;

[0021] Step 8. The finished plate is pre-stretched by 2% and subjected to paint baking treatment to obtain a plate after paint baking treatment.

[0022] In step 1, the process conditions for melting and refining are filtering and degassing using a 50ppi filter; the degassing is performed by an argon online degassing method, and the hydrogen content is controlled to be lower than 0.14ml / 100g Al.

[0023] In step 4, the solid solution treatment is performed by an industrial continuous annealing furnace, the furnace temperature is set to be 560-570℃, the strip passing speed is 24-28m / min, and the temperature rising speed is controlled to be 5-10℃ / s.

[0024] In step 4, the solid solution holding time controls the recrystallization degree of the plate and the solid solution degree of Mg and Si elements, and further controls the precipitation rule of the dispersed phase in the room temperature parking and baking process, which can be characterized by the diffusion distance △(C Mg , C Si ), that is: △(C Mg , C Si ) ∝ (wherein: C Mg , C Si are the atomic fractions of Mg and Si respectively, D is the diffusion distance, and t is the solid solution time).

[0025] Further, the solid solution treatment in step (4) has a total diffusion distance of the alloying elements as the solid solution amount S, that is: S= , (wherein: D0 is a pre-factor, taking 1.49×10 -5 m 2 / s; Q is the activation energy, taking 120.5 kJ / mol; and R is the gas constant, taking 8.314 J / (mol·K)).

[0026] In step 5, the quenching cooling is cooled by a combination of water spraying and strong wind; wherein the water spraying is 1-2 groups, the quenching cooling water temperature is controlled between 20℃-30℃, the wind intensity is 70%-95%, and when the aluminum alloy plate is cooled from the solid solution temperature to below 300℃, the cooling rate is 50℃ / s-100℃ / s.

[0027] In step 6, the plate after quenching cooling is subjected to straightening treatment with a deformation amount of 0.3%-0.8% within 60s.

[0028] In step 8, when the baking treatment is performed, the baking oven temperature is 185℃, and the holding time is 20min.

[0029] In step 8, after the baking treatment of the plate, according to the VDA (Verband der Automobilindustrie) 238 regulation, the bending of the finished plate to the maximum force, the bending measured angle is α when the loading is stopped by increasing 30N, and the conversion angle of the plate of different thicknesses is β, the conversion relationship between β and α is β=α×(b / 2) 1 / 2 (wherein b is the actual thickness of the plate), and β≥80°.

[0030] The technical scheme provided by the present application has the following innovations and technical progress:

[0031] The innovation of the present application is:

[0032] The present application proposes to functionally fit the solid solution time of the finished plate and the initial yield strength of the plate, and the function formula is (wherein: R p0.2 The fitting curve is highly coincident with the initial yield strength of the finished plate, and the optimal solid solution amount S can be determined based on the function fitting data, and the solid solution holding time is determined; the optimal solid solution holding time avoids the problems of high initial yield strength of the plate, poor formability of the plate caused by long solid solution time and high solid solution amount, and low baking paint strength of the plate caused by short solid solution time and insufficient solid solution amount. The solid solution time provided by the application can be directly used by an industrial continuous annealing furnace, eliminating the barrier between laboratory process research and industrial application, and improving the digital level of industrial production. The method for controlling the initial yield strength and baking paint strength of the alloy by controlling the solid solution amount can be applied to any 6-series aluminum alloy plate, even extruded profiles, reducing the number of tests, reducing test cost and cycle.

[0033] The technical progress of the application is embodied in:

[0034] 1. The application determines the optimal solid solution amount S, which can digitally control the initial yield strength of the plate, while avoiding the reduction of the baking paint strength. The principle is that the optimal solid solution amount can obtain appropriate Mg and Si solute atom solid solution degrees, appropriate initial yield strength, and then ensure the formability of the plate. During the baking paint treatment, Mg and Si solute atom clusters form more beta '' phases required for improving the baking paint hardening, thereby significantly improving the baking paint hardening performance of the plate, and then realizing the improvement of the crash performance of the material end.

[0035] 2. The optimal solid solution holding time can realize the precise control of the initial yield strength. The principle is that the Mg and Si solute atom concentration for forming precipitated strengthening phases is directly digitally controlled, the balance between the yield strength and the baking paint strength is realized, the test workload is reduced, the research and development cost is reduced for industrial production, the production efficiency is improved, and the digital control of the material performance is realized.

[0036] 3. The optimal solid solution heating speed matches the heating speed of the industrial continuous annealing furnace, and the heating speed can be controlled by the threading speed without the need for additional industrial continuous annealing furnace heating equipment, which has low operation technical requirements and is easy to implement on site.

[0037] 4. The optimal solid solution holding time fully considers the heating capacity of the industrial continuous annealing furnace, realizes the second-level control of the solid solution holding time, and improves the production efficiency of the industrial production continuous annealing furnace to a certain extent.

[0038] 5. The quenching cooling strength can be controlled by the number of cooling water switch groups, the cooling water temperature, and the fan strength of the existing industrial equipment, which has low understanding ability requirements for operators and is easy to operate.

[0039] 6. The optimal solid solution amount proposed by the present application can be precisely controlled by adjusting the continuous annealing furnace threading speed in industrial production, which has low operation technical requirements and does not need to add any measuring equipment or improve the equipment, and is easier to implement in industrial production site process.

[0040] 7. The optimal solid solution amount control method proposed by the present application improves the baking paint strength, guarantees excellent plate forming property, has high crash performance in the material stamping forming service process, and realizes the performance regulation and control of the material end to the application end.

[0041] 8. The optimal quenching process proposed by the present application guarantees that the plate has a bending angle of ≥80° after baking on the basis of guaranteeing the basic mechanical properties of the material, and improves the crash performance of the automobile parts in the material service process.

[0042] The beneficial technical effects of the present application are that the alloy has a more reasonable solute atom concentration than the conventional 6451 aluminum alloy after solid solution, has a suitable initial yield strength, can obtain a high bake hardening performance, and thus the automobile parts manufactured by the alloy have good crash performance. The plate obtained by the method not only has excellent mechanical properties and forming properties, but also has a high bake hardening performance, and the material cost is not increased, and is particularly suitable for high-strength automobile structural plate. DETAILED DESCRIPTION

[0043] The present application will be described in detail below in combination with specific embodiments.

[0044] In the development process of the 6451 aluminum alloy plate based on dynamic diffusion field regulation, the preparation process is strictly controlled to guarantee that the plate has a high bake hardening performance on the premise of low initial yield strength, and is better suitable for automobile structural parts with high forming property requirements, high strength requirements and high crash performance requirements.

[0045] The present application provides a 6451 aluminum alloy plate based on dynamic diffusion field regulation, which comprises the following components in percentage by mass: Si: 0.7wt.%~1.3wt.%, Fe: ≤0.5wt.%, Cu: ≤0.15wt.%, Mn: ≤0.20wt.%, Mg: 0.5wt.%~1.5wt.%, Cr: ≤0.10wt.%, Zn: ≤0.15wt.%, Ti: ≤0.10wt.%, and the balance is Al and impurities with a content of less than 0.05wt.%. The initial yield strength of the aluminum alloy plate is 104MPa~115MPa, the elongation is ≥25%, the solid solution amount is 4.18μm~8.64μm; the yield strength after baking is greater than 235MPa, and the bending angle after baking is ≥80°.

[0046] The aluminum alloy plate provided by the application has an initial yield strength and a solid solution amount conforming to a functional relationship formula:

[0047] ;

[0048] wherein R p0.2 is the initial yield strength, and S is the solid solution amount.

[0049] The application further provides a preparation method of the 6451 aluminum alloy plate based on dynamic diffusion field regulation, comprising the following steps:

[0050] Step 1. The components of the aluminum alloy plate are mixed according to the above-mentioned ratio, filtered and degassed by using a 50 ppi filter, and then cast into an ingot by using a semi-continuous casting device after melting and refining. The argon online degassing method is used for degassing, and the hydrogen content in the degassing process is controlled to be lower than 0.14 ml / 100g Al.

[0051] Step 2. After the ingot is cut and milled, homogenization treatment is performed at 540℃~580℃ for 6h~10h.

[0052] Step 3. The ingot after homogenization treatment is sequentially subjected to hot rolling, primary cold rolling, intermediate annealing and secondary cold rolling. The hot rolling starting temperature is 525℃~540℃, the hot rolling is performed until the plate thickness is 5mm~8mm, and the final rolling temperature is 260℃~280℃; the primary cold rolling is performed until the plate thickness is 3mm~4mm; the intermediate annealing temperature is 470℃~500℃, and the holding time is 20s~40s; the secondary cold rolling is performed until the plate thickness is 0.8mm~1.5mm; and the cold rolling reduction rate is ensured to be 50%~80%.

[0053] Step 4. The plate obtained by secondary cold rolling is subjected to solid solution treatment by using an industrial continuous annealing furnace, the furnace temperature is set to 560℃~570℃, the strip passing speed is 24m / min~28m / min, and the temperature rising speed is controlled to be 5℃ / s~10℃ / s. The solid solution treatment is performed at 560℃ for 7s~30s.

[0054] Step 5. The plate after solid solution treatment is quenched and cooled by using a water spraying and strong wind combination method: 1~2 groups of water spraying at 20℃~30℃ are used, and the wind intensity is adjusted to 70%~95% for cooling. When the plate is cooled from the solid solution temperature to below 300℃, the cooling rate is controlled to be 50℃ / s~100℃ / s.

[0055] Step 6. The plate after quenching and cooling is subjected to straightening treatment with a deformation amount of 0.3%~0.8% within 60s.

[0056] Step 7. The plate after straightening is transferred to a temperature of 60℃~100℃ within 3min and subjected to pre-aging treatment for 4h~10h to obtain a finished plate.

[0057] Step 8. After the finished plate is pre-stretched by 2%, an oil bath furnace is used to simulate baking paint, and the plate is kept at 185℃ for 20 min to obtain a plate after baking paint treatment.

[0058] Hereinafter, examples of the present application are listed, and the technical effects of the present application can be further verified according to these examples. However, the listed examples are only preferred embodiments of the present application, and should not be understood as limiting the scope of the above-mentioned subject matter of the present application to only this, and any technical solution formed on the basis of the technical concept of the present application falls within the protection scope of the present application.

[0059] Example 1:

[0060] The present embodiment provides a 6451 aluminum alloy plate based on dynamic diffusion field regulation, and the composition is as follows in terms of mass percentage: Si: 0.9wt.%, Mg: 0.7wt.%, Cu: 0.1wt.%, Mn: 0.1wt.%, Fe: 0.18wt.%, Cr: 0.03wt.%, Zn: 0.05wt.%, Ti: 0.02wt.%, and the balance is Al and impurities with a content of less than 0.05wt.%.

[0061] The present embodiment also provides a preparation method of the alloy plate, comprising the following steps:

[0062] Step 1. The alloy is mixed and melted according to the above-mentioned ratio, and the melt is refined (filtered by a filter with a pore size of 50 ppi, argon online degassing, and the hydrogen content is controlled to be 0.13 ml / 100g Al) and then cast into an ingot by using a semi-continuous casting device.

[0063] Step 2. After the ingot is cut and milled, it is subjected to homogenization treatment at a homogenization temperature of 560℃ for 8h.

[0064] Step 3. The ingot after homogenization treatment is sequentially subjected to hot rolling, primary cold rolling, intermediate annealing, and secondary cold rolling: the ingot is cooled to 530℃ and then hot rolled to a plate thickness of 6mm, and the final rolling temperature is 270℃; the primary cold rolling is to a plate thickness of 3.5mm, the intermediate annealing temperature is 485℃, the holding time is 30s, and the secondary cold rolling is to a plate thickness of 1.1mm, and the cold rolling reduction is 69%.

[0065] Step 4. The plate obtained by secondary cold rolling is subjected to solid solution treatment by using a continuous annealing furnace to obtain a plate with a solid solution amount S=6.11μm. The continuous annealing furnace temperature is set to 560℃, the strip passing speed is 26m / min, the temperature rising speed is controlled to be 6℃ / s, the solid solution treatment temperature is 560℃, and the holding time is 15s.

[0066] Step 5. The solution-treated plate is quenched in 3s, water spraying group 1, quenching cooling water temperature 25℃, wind intensity 80%, and the cooling rate is 80℃ / s when the temperature is reduced to below 300℃ from the solution temperature.

[0067] Step 6. The cooled plate is subjected to straightening treatment with a deformation amount of 0.5% in 1min.

[0068] Step 7. The straightened plate is transferred to a temperature of 75℃ for 8h, and finally a T4P state finished plate is obtained.

[0069] Step 8. After pre-stretching the T4P state finished plate by 2%, an oil bath furnace is used to simulate paint baking, and the plate is kept at 185℃ for 20min to obtain a plate after paint baking treatment.

[0070] Example 2:

[0071] The example provides a 6451 aluminum alloy plate based on dynamic diffusion field regulation, and the composition is as follows in terms of mass percentage: Si: 0.9wt.%, Mg: 0.7wt.%, Cu: 0.1wt.%, Mn: 0.1wt.%, Fe: 0.18wt.%, Cr: 0.03wt.%, Zn: 0.05wt.%, Ti: 0.02wt.%, and the balance is Al and impurities with a content of less than 0.05wt.%.

[0072] The example also provides a preparation method of the alloy plate, comprising the following steps:

[0073] Step 1. The alloy is mixed and melted according to the above ratio, and after refining treatment (filtration by using a filter with a pore size of 50 ppi, argon online degassing, and control of hydrogen content of 0.13ml / 100g Al), a cast ingot is cast by using a semi-continuous casting device.

[0074] Step 2. After the cast ingot is cut and milled, it is subjected to homogenization treatment at a homogenization temperature of 560℃ for 8h.

[0075] Step 3. The homogenized cast ingot is subjected to hot rolling, primary cold rolling, intermediate annealing, and secondary cold rolling in sequence: the cast ingot is cooled to 530℃ for hot rolling, and the hot rolling is performed to a plate thickness of 6mm, and the final rolling temperature is 270℃; the primary cold rolling is performed to a plate thickness of 3.5mm, the intermediate annealing temperature is 485℃, and the annealing time is 30s; the secondary cold rolling is performed to a plate thickness of 1.1mm, and the cold rolling reduction rate is 69%.

[0076] Step 4. The plate obtained by secondary cold rolling is subjected to solution treatment by using a continuous annealing furnace to obtain a plate with a solution amount S=6.11μm. The continuous annealing furnace temperature is set to 560℃, the strip passing speed is 24m / min, the temperature rising speed is controlled to 5℃ / s, the solution treatment temperature is 560℃, and the holding time is 15s.

[0077] Step 5. The solution-treated plate is quenched in 3s, water spraying group 1, quenching cooling water temperature 25℃, wind intensity 80%, and the cooling rate is 80℃ / s when the temperature is reduced to below 300℃ from the solution temperature.

[0078] Step 6. The cooled plate is subjected to straightening treatment with a deformation amount of 0.5% in 1min.

[0079] Step 7. The straightened plate is transferred to a temperature of 75℃ for 8h, and finally a T4P state finished plate is obtained.

[0080] Step 8. After pre-stretching the T4P state finished plate by 2%, an oil bath furnace is used to simulate paint baking, and the plate is kept at 185℃ for 20min to obtain a plate after paint baking treatment.

[0081] Example 3:

[0082] The embodiment provides a 6451 aluminum alloy plate based on dynamic diffusion field regulation, and the components are as follows in terms of mass percentage: Si: 0.9wt.%, Mg: 0.7wt.%, Cu: 0.1wt.%, Mn: 0.1wt.%, Fe: 0.18wt.%, Cr: 0.03wt.%, Zn: 0.05wt.%, Ti: 0.02wt.%, and the balance is Al and impurities with a content less than 0.05wt.%.

[0083] The embodiment also provides a preparation method of the alloy plate, including the following steps.

[0084] Step 1. The alloy is mixed and melted according to the above-mentioned proportion, and the melt is subjected to refining treatment (filtration by using a filter sheet with a pore size of 50 ppi, argon online degassing, and control of hydrogen content of 0.13ml / 100g Al) and then cast into an ingot by using a semi-continuous casting device.

[0085] Step 2. The ingot is subjected to homogenization treatment after being cut and milled, and the homogenization temperature is 560℃ and the holding time is 8h.

[0086] Step 3. The ingot after homogenization treatment is subjected to hot rolling, primary cold rolling, intermediate annealing and secondary cold rolling in sequence: the ingot is cooled to 530℃ and then hot rolled to a plate thickness of 6mm, and the final rolling temperature is 270℃; the plate is subjected to primary cold rolling to a thickness of 3.5mm, the intermediate annealing temperature is 485℃, the holding time is 30s, and the plate is subjected to secondary cold rolling to a thickness of 1.1mm, and the cold rolling reduction rate is 69%.

[0087] Step 4. The plate material obtained by secondary cold rolling is subjected to solid solution treatment by using a continuous annealing furnace to obtain a plate material with a solid solution amount S = 6.11 μm. The continuous annealing furnace is set at a temperature of 570 ℃, the strip passing speed is 28 m / min, the temperature rising speed is controlled at 10 ℃ / s, the solid solution treatment temperature is 560 ℃, and the holding time is 15 s.

[0088] Step 5. The plate material after solid solution treatment is quenched within 3 s, and the water spray is 1 group, the quenching cooling water temperature is 25 ℃, the wind intensity is 80%, and when the temperature is reduced to below 300 ℃ from the solid solution temperature, the cooling rate is 80 ℃ / s.

[0089] Step 6. The plate material after cooling is subjected to straightening treatment with a deformation amount of 0.5% within 1 min.

[0090] Step 7. The plate material after straightening is transferred to a temperature of 75 ℃ within 3 min and is held for 8 h to obtain a T4P state finished plate material.

[0091] Step 8. The T4P state finished plate material is pre-stretched by 2% and is subjected to paint baking simulation by using an oil bath furnace, and is held at a temperature of 185 ℃ for 20 min to obtain a plate material after paint baking treatment.

[0092] Example 4:

[0093] The example provides a 6451 aluminum alloy plate based on dynamic diffusion field regulation, and the composition is as follows in terms of mass percentage: Si: 0.9 wt.%, Mg: 0.7 wt.%, Cu: 0.1 wt.%, Mn: 0.1 wt.%, Fe: 0.18 wt.%, Cr: 0.03 wt.%, Zn: 0.05 wt.%, Ti: 0.02 wt.%, and the balance is Al and impurities with a content of less than 0.05 wt.%.

[0094] The example also provides a preparation method of the alloy plate, including the following steps.

[0095] Step 1. The alloy is melted according to the above-mentioned proportion, and the melt is subjected to refining treatment (filtration by using a filter sheet with a pore size of 50 ppi, argon online degassing, and control of hydrogen content of 0.13 ml / 100 g Al) and then is cast into an ingot by using a semi-continuous casting device.

[0096] Step 2. The ingot is subjected to homogenization treatment after head cutting and face milling, and the homogenization temperature is 560 ℃ and the holding time is 8 h.

[0097] Step 3. The ingot after homogenization treatment is subjected to hot rolling, primary cold rolling, intermediate annealing, and secondary cold rolling in sequence: the ingot is cooled to 530 ℃ to start hot rolling, the hot rolling is performed to a plate material thickness of 6 mm, and the final rolling temperature is 270 ℃; the primary cold rolling is performed to a plate material thickness of 3.5 mm, the intermediate annealing temperature is 485 ℃, the holding time is 30 s, the secondary cold rolling is performed to a plate material thickness of 1.1 mm, and the cold rolling reduction is 69%.

[0098] Step 4. The plate material obtained by secondary cold rolling is subjected to solid solution treatment by using a continuous annealing furnace to obtain a plate material with a solid solution amount S = 4.17 μm. The continuous annealing furnace is set at a temperature of 560 ℃, the strip passing speed is 26 m / min, the temperature rising speed is controlled at 6 ℃ / s, the solid solution treatment temperature is 560 ℃, and the holding time is 7 s.

[0099] Step 5. The plate material after solid solution treatment is quenched within 3 s, and the water spray is 1 group, the quenching cooling water temperature is 25 ℃, the wind intensity is 80%, and when the temperature is reduced to below 300 ℃ from the solid solution temperature, the cooling rate is 80 ℃ / s.

[0100] Step 6. The cooled plate material is subjected to straightening treatment with a deformation amount of 0.5% within 1 min.

[0101] Step 7. The straightened plate material is transferred to a temperature of 75 ℃ within 3 min and held for 8 h to obtain a T4P state finished plate material.

[0102] Step 8. The T4P state finished plate material is pre-stretched by 2% and then subjected to paint baking simulation by using an oil bath furnace, and is held at a temperature of 185 ℃ for 20 min to obtain a plate material after paint baking treatment.

[0103] Example 5:

[0104] The embodiment provides a 6451 aluminum alloy plate based on dynamic diffusion field regulation, and the components are as follows in terms of mass percentage: Si: 0.9 wt.%, Mg: 0.7 wt.%, Cu: 0.1 wt.%, Mn: 0.1 wt.%, Fe: 0.18 wt.%, Cr: 0.03 wt.%, Zn: 0.05 wt.%, Ti: 0.02 wt.%, and the balance is Al and impurities with a content less than 0.05 wt.%.

[0105] The embodiment also provides a preparation method of the alloy plate, which comprises the following steps.

[0106] Step 1. The alloy is melted according to the above-mentioned proportion, and after refining treatment (filtration by using a filter sheet with a pore size of 50 ppi, argon online degassing, and control of hydrogen content of 0.13 ml / 100 g Al), the melt is cast into an ingot by using a semi-continuous casting device.

[0107] Step 2. The ingot is subjected to homogenization treatment after head cutting and face milling, and the homogenization temperature is 560 ℃ and the holding time is 8 h.

[0108] Step 3. The homogenized ingot is sequentially subjected to hot rolling, primary cold rolling, intermediate annealing, and secondary cold rolling: the ingot is cooled to 530℃ and then hot rolled to a plate thickness of 6mm, with a final rolling temperature of 270℃; the plate is primary cold rolled to a thickness of 3.5mm, with an intermediate annealing temperature of 485℃ and a holding time of 30s; and the plate is secondary cold rolled to a thickness of 1.1mm, with a cold rolling reduction of 69%.

[0109] Step 4. The plate obtained by secondary cold rolling is subjected to solid solution treatment using a continuous annealing furnace, to obtain a plate with a solid solution amount S = 8.64μm. The continuous annealing furnace is set to a temperature of 560℃, with a strip passing speed of 26m / min and a controlled temperature rising speed of 6℃ / s. The solid solution treatment temperature is 560℃, and the holding time is 30s.

[0110] Step 5. The solid-solution-treated plate is quenched within 3s, with water spraying for 1 group and a quenching cooling water temperature of 25℃. The wind intensity is 80%, and the cooling rate is 80℃ / s when the temperature is reduced from the solid solution temperature to below 300℃.

[0111] Step 6. The cooled plate is subjected to straightening treatment with a deformation amount of 0.5% within 1min.

[0112] Step 7. The straightened plate is transferred to a temperature of 75℃ within 3min and held for 8h, to finally obtain a T4P state finished plate.

[0113] Step 8. After pre-stretching the T4P state finished plate by 2%, an oil bath furnace is used to simulate paint baking, with a holding temperature of 185℃ and a holding time of 20min, to obtain a plate after paint baking treatment.

[0114] Example 6:

[0115] The present embodiment provides a 6451 aluminum alloy plate based on dynamic diffusion field regulation, with a composition in terms of mass percentage of: Si: 0.9wt.%, Mg: 0.7wt.%, Cu: 0.1wt.%, Mn: 0.1wt.%, Fe: 0.18wt.%, Cr: 0.03wt.%, Zn: 0.05wt.%, Ti: 0.02wt.%, and the balance being Al and impurities with a content of less than 0.05wt.%.

[0116] The present embodiment also provides a preparation method of the alloy plate, comprising the following steps:

[0117] Step 1. The alloy is melted according to the above-mentioned proportion, and the melt is subjected to refining treatment (filtration using a filter with a pore size of 50ppi, online argon gas degassing, and control of hydrogen content of 0.13ml / 100g Al) and then cast into an ingot using a semi-continuous casting device.

[0118] Step 2. The ingot is subjected to homogenization treatment after head cutting and face milling, with a homogenization temperature of 560℃ and a holding time of 8h.

[0119] Step 3. The homogenized ingot was sequentially subjected to hot rolling, primary cold rolling, intermediate annealing, and secondary cold rolling: the ingot was cooled to 530℃ and then hot rolled to a plate thickness of 6mm, with a final rolling temperature of 270℃; the plate was primary cold rolled to a thickness of 3.5mm, with an intermediate annealing temperature of 485℃ and a holding time of 30s; and the plate was secondary cold rolled to a thickness of 1.1mm, with a cold rolling reduction of 69%.

[0120] Step 4. The plate obtained by secondary cold rolling was subjected to solid solution treatment using a continuous annealing furnace, obtaining a plate with a solid solution amount S = 6.11μm. The continuous annealing furnace was set to a temperature of 560℃, with a strip passing speed of 26m / min and a controlled temperature rising speed of 6℃ / s. The solid solution treatment temperature was 560℃, with a holding time of 15s.

[0121] Step 5. The solid-solution-treated plate was quenched within 3s, with water spraying for 1 group and a quenching cooling water temperature of 30℃. When the temperature was reduced to below 300℃, the cooling rate was 50℃ / s.

[0122] Step 6. The cooled plate was subjected to straightening treatment with a deformation amount of 0.5% within 1min.

[0123] Step 7. The straightened plate was transferred to a temperature of 75℃ within 3min and held for 8h, finally obtaining a T4P-state finished plate.

[0124] Step 8. After pre-stretching the T4P-state finished plate by 2%, an oil bath furnace was used to simulate paint baking, with a holding temperature of 185℃ and a holding time of 20min, obtaining a plate after paint baking treatment.

[0125] Example 7:

[0126] The example provides a 6451 aluminum alloy plate based on dynamic diffusion field regulation, with a composition in terms of mass percentage of: Si: 0.9wt.%, Mg: 0.7wt.%, Cu: 0.1wt.%, Mn: 0.1wt.%, Fe: 0.18wt.%, Cr: 0.03wt.%, Zn: 0.05wt.%, Ti: 0.02wt.%, and the balance being Al and impurities with a content of less than 0.05wt.%.

[0127] The example also provides a preparation method of the alloy plate, including the following steps:

[0128] Step 1. The alloy was melted according to the above-mentioned proportion, and the melt was subjected to refining treatment (filtration using a filter with a pore size of 50ppi, online argon degassing, and control of hydrogen content of 0.13ml / 100g Al) and then cast into an ingot using a semi-continuous casting device.

[0129] Step 2. The ingot is cut and milled, and then subjected to homogenization treatment at a temperature of 560℃ for 8h.

[0130] Step 3. The homogenized ingot is subjected to hot rolling, first cold rolling, intermediate annealing, and second cold rolling in sequence: the ingot is cooled to 530℃ and then subjected to hot rolling, and the hot-rolled plate has a thickness of 6mm, with a final rolling temperature of 270℃; the first cold rolling is performed to a plate thickness of 3.5mm, with an intermediate annealing temperature of 485℃ and an annealing duration of 30s; and the second cold rolling is performed to a plate thickness of 1.1mm, with a cold rolling reduction rate of 69%.

[0131] Step 4. The plate obtained by the second cold rolling is subjected to solid solution treatment using a continuous annealing furnace, to obtain a plate with a solid solution amount S=6.11μm. The continuous annealing furnace is set to a temperature of 560℃, with a strip speed of 26m / min and a controlled temperature rising speed of 6℃ / s, and the solid solution treatment is performed at a temperature of 560℃ for 15s.

[0132] Step 5. The solid-solution-treated plate is quenched within 3s, with 2 groups of water spraying, a quenching cooling water temperature of 20℃, and a wind intensity of 95%, and the cooling rate is 100℃ / s when the temperature is reduced to below 300℃.

[0133] Step 6. The cooled plate is subjected to straightening treatment with a deformation amount of 0.5% within 1min.

[0134] Step 7. The straightened plate is transferred to a temperature of 75℃ within 3min and is kept at this temperature for 8h, to obtain a T4P-state finished plate.

[0135] Step 8. The T4P-state finished plate is pre-stretched by 2%, and then is subjected to paint baking simulation using an oil bath furnace, at a temperature of 185℃ for 20min, to obtain a plate after paint baking treatment.

[0136] Comparative Example 1

[0137] The present comparative example provides an aluminum alloy plate, with a composition in terms of mass percentage of: Si: 0.9wt.%, Mg: 0.7wt.%, Cu: 0.1wt.%, Mn: 0.1wt.%, Fe: 0.18wt.%, Cr: 0.03wt.%, Zn: 0.05wt.%, Ti: 0.02wt.%, and the balance being Al and impurities each having a content of less than 0.05wt.%.

[0138] The present comparative example also provides a preparation method of the aluminum alloy plate, comprising the following steps:

[0139] The alloy is melted according to the above-mentioned proportion, and the melt is refined (filtered by using a filter sheet with a pore size of 50 ppi, argon online degassing, and the hydrogen content is controlled to be 0.13 ml / 100g Al) and then cast into an ingot by using a semi-continuous casting equipment; after the ingot is cut and milled, homogenization treatment is performed, the homogenization temperature is 560℃, and the holding time is 8h; then the temperature is lowered to 530℃ for rolling, and rolled to 6mm, the final rolling temperature is 270℃; once cold-rolled to 3.5mm, the intermediate annealing temperature is 485℃, the holding time is 30s, twice cold-rolled to 1.1mm, the cold-rolling reduction is 69%, the intermediate annealing temperature is 485℃, the holding time is 30s, then solid solution treatment is performed, the continuous annealing furnace temperature is set to 555℃, the strip passing speed is 23m / min, the heating rate is controlled to be 4℃ / s, the solid solution treatment temperature is 560℃, the holding time is 15s, the solid solution amount S=6.11μm, 3s quenching, 1 group of water spraying, the quenching cooling water temperature is 25℃, the wind intensity is 80%, when the temperature is lowered to below 300℃ from the solid solution temperature, the cooling rate is 80℃ / s, after cooling, 0.5% deformation amount of straightening treatment is performed within 1min, the solid solution treated plate is transferred to 75℃ within 3min and held for 8h, and finally a T4P state finished plate is obtained. After the T4P state finished plate is pre-stretched by 2%, an oil bath furnace is used to simulate paint baking, the temperature is held at 185℃ for 20min, and a paint baked plate is obtained.

[0140] Comparative Example 2:

[0141] The present comparative example provides an aluminum alloy plate, the composition is as follows in terms of mass percentage: Si: 0.9wt.%, Mg: 0.7wt.%, Cu: 0.1wt.%, Mn: 0.1wt.%, Fe: 0.18wt.%, Cr: 0.03wt.%, Zn: 0.05wt.%, Ti: 0.02wt.%, and the balance is Al and impurities with a content of less than 0.05wt.%.

[0142] The present comparative example also provides a preparation method of the aluminum alloy plate, comprising the following steps:

[0143] The alloy is melted according to the above-mentioned proportion, and the melt is refined (filtered by using a filter sheet with a pore size of 50 ppi, argon online degassing, and the hydrogen content is controlled to be 0.13 ml / 100g Al) and then cast into an ingot by using a semi-continuous casting equipment; after the ingot is cut and milled, homogenization treatment is performed, the homogenization temperature is 560℃, and the holding time is 8h; then the temperature is lowered to 530℃ for rolling, and rolled to 6mm, the final rolling temperature is 270℃; once cold-rolled to 3.5mm, the intermediate annealing temperature is 485℃, the holding time is 30s, twice cold-rolled to 1.1mm, the cold-rolling reduction is 69%, the intermediate annealing temperature is 485℃, the holding time is 30s, then solid solution treatment is performed, the continuous annealing furnace temperature is set to 575℃, the strip passing speed is 29m / min, the heating rate is controlled to be 12℃ / s, the solid solution treatment temperature is 560℃, the holding time is 15s, the solid solution amount S=6.11μm, 3s quenching, 1 group of water spraying, the quenching cooling water temperature is 25℃, the wind intensity is 80%, when the temperature is lowered to below 300℃ from the solid solution temperature, the cooling rate is 80℃ / s, after cooling, 0.5% deformation amount of straightening treatment is performed within 1min, the solid solution treated plate is transferred to 75℃ within 3min and held for 8h, and finally a T4P state finished plate is obtained. After the T4P state finished plate is pre-stretched by 2%, an oil bath furnace is used to simulate paint baking, the temperature is held at 185℃ for 20min, and a paint baked plate is obtained.

[0144] Comparative Example 3:

[0145] The present comparative example provides an aluminum alloy plate, the composition is as follows in terms of mass percentage: Si: 0.9wt.%, Mg: 0.7wt.%, Cu: 0.1wt.%, Mn: 0.1wt.%, Fe: 0.18wt.%, Cr: 0.03wt.%, Zn: 0.05wt.%, Ti: 0.02wt.%, and the balance is Al and impurities with a content of less than 0.05wt.%.

[0146] The present comparative example also provides a preparation method of the aluminum alloy plate, comprising the following steps:

[0147] The alloy is melted according to the above-mentioned proportion, and the melt is refined (filtered by using a filter sheet with a pore size of 50 ppi, argon online degassing, and the hydrogen content is controlled to be 0.13 ml / 100g Al) and then cast into an ingot by using a semi-continuous casting equipment; after the ingot is cut and milled, it is subjected to homogenization treatment, the homogenization temperature is 560℃, and the holding time is 8h; then it is cooled to 530℃ and rolled, rolled to 6mm, and the final rolling temperature is 270℃; once cold-rolled to 3.5mm, the intermediate annealing temperature is 485℃, the holding time is 30s, twice cold-rolled to 1.1mm, the cold-rolling reduction is 69%, the intermediate annealing temperature is 485℃, the holding time is 30s, then subjected to solid solution treatment, the continuous annealing furnace temperature is set to 560℃, the strip passing speed is 26m / min, the temperature rising speed is controlled to be 6℃ / s, the solid solution treatment temperature is 560℃, the holding time is 4s, the solid solution amount S=3.16μm, quenched within 3s, 1 group of water spraying, the quenching cooling water temperature is 25℃, the wind intensity is 80%, when the temperature is reduced to below 300℃ from the solid solution temperature, the cooling rate is 80℃ / s, after cooling, straightened within 1min with a deformation of 0.5%, the solid solution treated plate is transferred to a temperature of 75℃ within 3min and held for 8h, and finally a T4P state finished plate is obtained. After the T4P state finished plate is pre-stretched by 2%, an oil bath furnace is used to simulate paint baking, and the plate is held at 185℃ for 20min to obtain a plate after paint baking treatment.

[0148] Comparative Example 4:

[0149] The present comparative example provides an aluminum alloy plate, the composition is as follows in terms of mass percentage: Si: 0.9wt.%, Mg: 0.7wt.%, Cu: 0.1wt.%, Mn: 0.1wt.%, Fe: 0.18wt.%, Cr: 0.03wt.%, Zn: 0.05wt.%, Ti: 0.02wt.%, and the balance is Al and impurities with a content of less than 0.05wt.%.

[0150] The present comparative example also provides a preparation method of the aluminum alloy plate, comprising the following steps:

[0151] The alloy was melted according to the above-mentioned proportion, and the melt was refined (filtered by a filter sheet with a pore size of 50 ppi, on-line argon degassing, and the hydrogen content was controlled to be 0.13 ml / 100g Al) and then cast into an ingot by using a semi-continuous casting equipment; the ingot was cut and milled, and then subjected to homogenization treatment at a homogenization temperature of 560°C for 8h; then, the temperature was lowered to 530°C for rolling, and rolled to 6mm at a finish rolling temperature of 270°C; once cold-rolled to 3.5mm at an intermediate annealing temperature of 485°C for 30s, twice cold-rolled to 1.1mm at a cold-rolling reduction rate of 69% and an intermediate annealing temperature of 485°C for 30s, then subjected to solid solution treatment, the continuous annealing furnace temperature was set to 560°C, the strip passing speed was 26m / min, the temperature rising speed was controlled to be 6°C / s, the solid solution treatment temperature was 560°C, the holding time was 31s, the solid solution amount S=8.79μm, 3s quenching, 1 group of water spraying, quenching cooling water temperature was 25°C, air intensity was 80%, when the temperature was lowered to below 300°C from the solid solution temperature, the cooling rate was 80°C / s, after cooling, the plate was subjected to straightening treatment with a deformation amount of 0.5% within 1min, the plate after solid solution treatment was transferred to a temperature of 75°C within 3min and held for 8h, and finally a T4P state finished plate was obtained. The T4P state finished plate was pre-stretched by 2%, and then subjected to paint baking treatment in an oil bath furnace to obtain a plate after paint baking treatment at a temperature of 185°C for 20min.

[0152] Comparative Example 5:

[0153] The present comparative example provides an aluminum alloy plate, the components are as follows in mass percentage: Si: 0.9wt.%, Mg: 0.7wt.%, Cu: 0.1wt.%, Mn: 0.1wt.%, Fe: 0.18wt.%, Cr: 0.03wt.%, Zn: 0.05wt.%, Ti: 0.02wt.%, and the balance is Al and impurities with a content of less than 0.05wt.%.

[0154] The present comparative example also provides a preparation method of the aluminum alloy plate, comprising the following steps:

[0155] The alloy was melted according to the above-mentioned proportion, and the melt was refined (filtered by a filter sheet with a pore size of 50 ppi, on-line argon degassing, and the hydrogen content was controlled to be 0.13 ml / 100g Al) and then cast into an ingot by using a semi-continuous casting equipment; the ingot was cut and milled, and then subjected to homogenization treatment at a homogenization temperature of 560°C for 8h; then, the temperature was lowered to 530°C for rolling, and rolled to 6mm at a finish rolling temperature of 270°C; once cold-rolled to 3.5mm at an intermediate annealing temperature of 485°C for 30s, twice cold-rolled to 1.1mm at a cold-rolling reduction rate of 69% and an intermediate annealing temperature of 485°C for 30s, and then subjected to solid solution treatment at a continuous annealing furnace temperature of 560°C, a strip passing speed of 26m / min, a temperature rising speed of 6°C / s, a solid solution treatment temperature of 560°C, a holding time of 15s, a solid solution amount S=6.11μm, quenching within 3s, water spraying off, a strong wind cooling intensity of 60%, a cooling rate of 30°C / s when the temperature was lowered to below 300°C from the solid solution temperature, and straightening treatment at a deformation amount of 0.5% within 1min after cooling, and then the plate after solid solution treatment was transferred to a temperature of 75°C within 3min and held for 8h, to obtain a T4P state finished plate. The T4P state finished plate was pre-stretched by 2%, and then subjected to paint baking by using an oil bath furnace, and held at 185°C for 20min, to obtain a plate after paint baking.

[0156] Comparative Example 6:

[0157] The present comparative example provides an aluminum alloy plate, and the components are as follows in terms of mass percentage: Si: 0.9wt.%, Mg: 0.7wt.%, Cu: 0.1wt.%, Mn: 0.1wt.%, Fe: 0.18wt.%, Cr: 0.03wt.%, Zn: 0.05wt.%, Ti: 0.02wt.%, and the balance is Al and impurities with a content of less than 0.05wt.%.

[0158] The present comparative example also provides a preparation method of the aluminum alloy plate, comprising the following steps:

[0159] The alloy is melted according to the above-mentioned proportion, and the melt is refined (filtered by using a filter sheet with a pore size of 50 ppi, argon online degassing, and the hydrogen content is controlled to be 0.13 ml / 100g Al) and then cast into an ingot by using a semi-continuous casting equipment; after the ingot is cut and milled, homogenization treatment is performed, the homogenization temperature is 560℃, and the holding time is 8h; then the temperature is lowered to 530℃ for rolling, and rolled to 6mm, the final rolling temperature is 270℃; once cold-rolled to 3.5mm, the intermediate annealing temperature is 485℃, the holding time is 30s, twice cold-rolled to 1.1mm, the cold-rolling reduction is 69%, the intermediate annealing temperature is 485℃, the holding time is 30s, then solid solution treatment is performed, the continuous annealing furnace temperature is set to 560℃, the strip passing speed is 26m / min, the heating rate is controlled to be 6℃ / s, the solid solution treatment temperature is 560℃, the holding time is 15s, the solid solution amount S=6.11μm, 3s quenching, 3 groups of water spraying, the quenching cooling water temperature is 20℃, the wind intensity is 100%, when the temperature is lowered to below 300℃ from the solid solution temperature, the cooling rate is 120℃ / s, after cooling, 0.5% deformation amount of straightening treatment is performed within 1min, the solid solution treated plate is transferred to 75℃ within 3min and held for 8h, and finally a T4P state finished plate is obtained. After the T4P state finished plate is pre-stretched by 2%, an oil bath furnace is used to simulate paint baking, the temperature is 185℃, and the holding time is 20min, and a paint baked plate is obtained.

[0160] Comparative Example 7:

[0161] The present comparative example provides an aluminum alloy plate, the components are as follows in mass percentage: Si: 0.9wt.%, Mg: 0.7wt.%, Cu: 0.1wt.%, Mn: 0.1wt.%, Fe: 0.18wt.%, Cr: 0.03wt.%, Zn: 0.05wt.%, Ti: 0.02wt.%, and the balance is Al and impurities with a content of less than 0.05wt.%.

[0162] The present comparative example also provides a preparation method of the aluminum alloy plate, comprising the following steps:

[0163] The alloy was melted according to the above-mentioned proportion, and the melt was treated by refining (filtered by a filter sheet with a pore size of 50 ppi, argon online degassing, and the hydrogen content was controlled to be 0.13 ml / 100g Al) and then cast into an ingot by using a semi-continuous casting equipment; after the ingot was cut and milled, it was subjected to homogenization treatment at a homogenization temperature of 560°C for 8h; then it was cooled to 530°C and rolled, and rolled to 6mm at a finish rolling temperature of 270°C; once cold-rolled to 3.5mm, the intermediate annealing temperature was 485°C, and the annealing time was 30s, and then twice cold-rolled to 1.1mm, the cold rolling reduction was 69%, and then subjected to solid solution treatment, the continuous annealing furnace temperature was set to 560°C, the strip passing speed was 26m / min, the temperature rising speed was controlled to be 6°C / s, the solid solution treatment temperature was 560°C, the holding time was 15s, the solid solution amount S=6.11μm, quenched within 3s, water spraying was 2 groups, the quenching cooling water temperature was 25°C, and after cooling, the plate was subjected to straightening treatment with a deformation amount of 0.5% within 1min, and then the plate after solid solution treatment was transferred to a temperature of 75°C within 3min and held for 8h, and finally a T4P state finished plate was obtained. After the T4P state finished plate was pre-stretched by 2%, an oil bath furnace was used to simulate paint baking, and the plate was held at 185°C for 20min to obtain a plate after paint baking treatment.

[0164]

Performance Test

[0165] 1. Mechanical property test:

[0166] The T4P state finished plates obtained in each example and comparative example were stored for 7 days, and then the yield strength (R p0.2 ), tensile strength (R m ), and elongation (A 50 ) of the plates were tested; the yield strength (R p0.2 / BH) and tensile strength (R m / BH) of the plates after paint baking treatment were tested. All the mechanical property test samples were sampled along the vertical rolling direction, and the sample size was A50 tensile sample recommended by GB / T228, and the test results are shown in Table 1.

[0167] 2. Evaluation of bending performance:

[0168] A sample with a length of 60mm and a width of 60mm was taken from the plate after paint baking treatment along the rolling direction, and then loaded along the center axis of the sample to the maximum load and continued to load 30N, and then the bending measured angle a was measured after unloading, and the thickness conversion angle was β=α×(b / 2) 1 / 2 (wherein b is the actual thickness of the plate), and the test results are shown in Table 1.

[0169] Table 1: Mechanical properties, paint baking, and bending angle of examples;

[0170] ;

[0171] From Table 1, it can be seen that the initial yield strength of the plates of Examples 1-7 is maintained at 104-115 MPa, and the elongation is ≥25%, meeting the requirements for plate stamping; after 2% pre-stretching + 185℃x20min simulated paint baking, the yield strength is greater than 235 MPa, and the bending angle is greater than 80°, which can be used as high-strength automobile structural parts. In the comparative examples, because Comparative Examples 1-7 do not meet the requirements of the present application, the following results are obtained:

[0172] A. Comparative Example 1 has a slow solid solution heating speed, and the strip passes through the entire length of the continuous annealing furnace, and is in the heating process, resulting in a serious lack of holding time, and thus the solid solution amount cannot be guaranteed, resulting in too low alloy strength, which cannot meet the performance requirements;

[0173] B. Comparative Example 2 has a too fast solid solution heating speed, and the solute atoms are in a back-dissolution state after reaching the temperature, resulting in an increase in the solid solution amount, and thus the alloy strength is too high, and the bending performance is less than 80°, which cannot meet the performance requirements;

[0174] C. Comparative Example 3 has a too short solid solution holding time, and the solid solution amount is insufficient, and the solubility of solute atoms is too low, and in the subsequent aging process, the amount of strengthening phase precipitated is insufficient, resulting in insufficient strength, which cannot meet the performance requirements;

[0175] D. Comparative Example 4 has a too long solid solution holding time, and the solid solution amount is too high, and the solubility of solute atoms is too high, resulting in too high initial yield strength, and the forming performance is reduced, and at the same time, the bending angle after paint baking is small, which does not meet the performance requirements.

[0176] E. Comparative Example 5 has a slow cooling speed, and the solute atoms precipitate during the cooling process, resulting in a high initial yield strength of the alloy, which cannot guarantee the formability of the material; during the paint baking heat treatment process, the size of the precipitated phase increases, and the bending performance of the material is deteriorated.

[0177] F. Comparative Example 6 has a too fast cooling speed, and the strip produces internal stress, although the mechanical properties of the strip meet the requirements, but the flatness of the strip is poor, and the stamping springback is large, which cannot meet the performance requirements.

[0178] G. Comparative Example 7 directly uses water quenching without combining with strong wind, resulting in a high temperature of the strip, and the temperature of the strip after passing through the quenching zone of the continuous annealing furnace is higher than 180℃, while the surface of the transmission roller is polyurethane material, which can resist a temperature lower than 150℃, resulting in melting of the transmission rubber roller and adhering to the surface of the strip, which is scrapped and cannot be tested for performance.

[0179] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application but not to limit it. Although the present application has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the specific embodiments of the present application can be modified or equivalently replaced without departing from the spirit and scope of the present application, and any modification or equivalent replacement should be covered within the protection scope of the present application.

Claims

1. A 6451 aluminum alloy plate based on dynamic diffusion field regulation, characterized in that, The aluminum alloy plate includes the following components by mass percentage: Si: 0.7wt.%~1.3wt.%, Fe: ≤0.5wt.%, Cu: ≤0.15wt.%, Mn: ≤0.20wt.%, Mg: 0.5wt.%~1.5wt.%, Cr: ≤0.10wt.%, Zn: ≤0.15wt.%, Ti: ≤0.10wt.%, the balance being Al and impurities each having a content less than 0.05wt.%; The aluminum alloy plate has a solid solution amount of 4.18μm~8.64μm; The initial yield strength of the aluminum alloy plate and the solid solution amount satisfy a functional relationship: ； where R p0.2 is the initial yield strength, S is the solid solution content; The preparation method of the 6451 aluminum alloy plate based on dynamic diffusion field regulation comprises the following steps: Step 1. Mix the components of the aluminum alloy plate according to the proportions, melt and refine, and then use a semi-continuous casting device to cast into ingots; Step 2. Homogenize the ingots: control the heating temperature to be 540℃-580℃ and the holding time to be 6h-10h; Step 3. The homogenized ingots are sequentially subjected to hot rolling, primary cold rolling, intermediate annealing, and secondary cold rolling; the hot rolling process is as follows: the opening rolling temperature is 525℃-540℃, the hot rolling is performed to a plate thickness of 5mm-8mm, and the final rolling temperature is 260℃-280℃; the primary cold rolling is performed to a plate thickness of 3mm-4mm; the intermediate annealing temperature is 470℃-500℃, and the holding time is 20s-40s; the secondary cold rolling is performed to a plate thickness of 0.8mm~1.5mm; and the cold rolling reduction rate is ensured to be 50%-80%; Step 4. The plate obtained by secondary cold rolling is subjected to solid solution treatment: the holding temperature is 560℃, and the holding time is 7s-15s; Step 5. The solid-solution-treated plate is quenched at a set cooling rate by combining spray with strong wind cooling; Step 6. The quenched plate is straightened; Step 7. The straightened plate is transferred to a temperature of 60℃~100℃ for 4h-10h of pre-aging treatment to obtain a finished plate; Step 8. The finished plate is pre-stretched by 2% and then subjected to paint baking treatment to obtain a paint-baked plate; In step 4, the solid solution treatment is performed using an industrial continuous annealing furnace, the furnace temperature is set to 560℃-570℃, the strip passing speed is 24m / min-28m / min, and the temperature rising speed is controlled to be 5℃ / s-10℃ / s; The yield strength of the alloy plate after paint baking treatment is greater than 235MPa, and the bending angle is ≥80°.

2. The 6451 aluminum alloy plate based on dynamic diffusion field regulation according to claim 1, characterized in that, The initial yield strength of the aluminum alloy plate is 104MPa-115MPa, and the elongation is ≥25%.

3. The 6451 aluminum alloy plate based on dynamic diffusion field regulation according to claim 1, characterized in that, In step 1, the melting and refining are performed by filtering and degassing using a filter; the degassing is performed using an argon online degassing method, and the hydrogen content during the degassing process is controlled to be less than 0.14ml / 100g Al.

4. The 6451 aluminum alloy plate based on dynamic diffusion field regulation according to claim 1, characterized in that, In step 5, the quenching cooling is performed using a combination of water spraying and strong wind, 1-2 groups of water spraying are used, the quenching cooling water temperature is controlled to be between 20℃-30℃, and the wind intensity is 70%-95%; when the plate is cooled from the solid solution temperature to below 300℃, the cooling rate is 50℃ / s-100℃ / s.

5. The 6451 aluminum alloy plate based on dynamic diffusion field regulation according to claim 1, characterized in that, In step 6, the quenched alloy plate is straightened within 60 seconds with a deformation of 0.3% to 0.8%.

6. The 6451 aluminum alloy plate based on dynamic diffusion field regulation according to claim 1, characterized in that, In step 8, the baking temperature is 185°C and the holding time is 20 minutes.

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